Device for replacing a cardiac valve by percutaneous route

ABSTRACT

A device for replacing a cardiac valve includes an elongated support element ( 2 ), two series of elongated blades ( 30 ) arranged around the circumference of the elongated elements ( 2 ), where the blades ( 30 ) have opposite cutting edges ( 30   a   , 30   b ) and can be extended corolla-shaped such that their cutting edges are set in the extension of one another thereby forming circular cutting edges. The blades ( 30 ) can be brought closer together so that their circular cutting edges are urged to cut the native valve ( 55, 56 ) so as to separate it from the corporeal duct ( 50 ).

The present invention relates to a device for replacing a heart valve bya percutaneous route.

Replacing a defective heart valve is currently usually performed byopening up the thorax, placing the patient under extra-corporalcirculation, temporarily stopping the heart, and opening up the heart soas to cut away and replace the valve.

These successive steps in the operation have the disadvantage ofentailing hospitalizing the patient for a relatively long period of timeand of being complicated and expensive.

To overcome this drawback it has been envisaged for a heart valve to bereplaced by a route which is not so invasive. International (PCT)applications Ser. Nos. WO 93/01768 and WO 97/28807, and U.S. Pat. Nos.5,814,097, 5,370,685 and 5,545,214 illustrate some known fairlynon-invasive techniques and instruments for performing these techniques.

The existing techniques are, however, considered not to be perfectlysatisfactory and to be open to improvement. In particular, thesetechniques have the disadvantage of always involving placing the patientunder extra-corporal circulation and temporarily stopping the heart;they are difficult to put into practice; they do not allow precisecontrol over the diameter at which the native valve is cut with a viewto subsequently calibrating the prosthetic valve; they run the risk thatfragments of, often calcified, native valve will become dispersed intothe organism, which may lead to an embolism, and the risks ofperforating the wall of the aorta or the heart; they also introduce therisks of acute reflux of blood during ablation of the native valve.

The device according to the present invention has been designed with aview to alleviating the deficiencies of these techniques.

In particular, the object of the invention is to provide a device whichis satisfactory as regards the cutting-away and replacement of thevalve, by making it possible to perform the intervention without openingup the thorax, stopping the heart and/or opening up the heart, and bymaking it possible to prevent any dispersion of fragments of the removedvalve into the circulatory system.

The terms “distal” and “proximal” used hereinbelow to explain theinvention are defined with respect to the direction in which the bloodflows.

The device according to the invention comprises:

an elongate support element;

a first series of elongate blades arranged around the circumference ofsaid elongate element; these blades are pivotably connected to theelongate element at their proximal longitudinal end and each have acutting edge at their distal longitudinal end; these blades can pivotwith respect to the elongate element between a furled position in whichthey are near to the wall of the elongate element so that they do notimpede the introduction and sliding of the device into and in the bodilyvessel in which the valve is located, particularly within the aorta, andan unfurled position in which these blades are deployed into a corollain such a way that their cutting edges are placed in the continuation ofone another and thus constitute a circular cutting edge;

a second series of blades which is arranged after said first series ofblades in the distal direction; the blades of this second series ofblades have a structure identical to that of the blades of said firstseries of blades except that these blades of this second series areconnected to the elongate element by their distal longitudinal end andeach have a cutting edge at their proximal longitudinal end;

means for bringing the blades of said first and second series of bladesfrom their furled position to their unfurled position;

means for moving said series of blades axially toward one another,between a position in which these series of blades are away from eachother and in which one series of blades can be placed axially on oneside of the native valve while the other series of blades is placedaxially on the other side of this valve, and a close-together positionin which the circular cutting edges of these two series of blades arebrought into mutual contact and thus cut through the native valve so asto detach it from said bodily vessel; and

means of identifying, by a percutaneous route, the axial position of thedevice with respect to the native valve so as to position each of thetwo aforementioned series of blades on one side of this valve.

The device according to the invention may be introduced percutaneouslyinto said bodily vessel and slid along this vessel until each of theaforementioned series of blades is placed on one side of the valve. Thisposition is identified using said identifying means.

A peripheral profusion or extra corporal circulation system may be setin place to facilitate the flow of the blood, with a view to preventingblood from pooling in the heart.

After the aforementioned positioning of the device, the blades of thetwo series of blades are deployed, then these two series are broughtcloser together until they cut through the valve. The shaping of theseblades allows this cutting to be performed in a single operation,therefore without generating fragments likely to be dispersed into thecirculatory system, or at the very least generating only very few suchfragments; this shaping also allows precise control over the diameter atwhich the native valve is cut, with a view to subsequent calibration ofthe prosthetic valve.

The blades are then returned to the furled position.

The prosthetic valve is then put in place.

This valve may be separate from the device, in which case the latter isremoved, then the prosthetic valve is introduced and positioned in thesaid bodily vessel by means of a separate device. As a preference,however, the device according to the invention comprises a proximalprosthetic valve, with a radially deployable structure, it beingpossible for this prosthetic valve to occupy a furled position in whichit is near the wall of said elongate element and does not impede theintroduction and sliding of the device into and in said bodily vessel,and an unfurled position in which it bears against the wall of thisvessel and is able to replace the native heart valve.

The device thus allows the prosthetic valve to be introduced andpositioned at the appropriate point in the bodily vessel, through thesame action as the one which allowed the native valve to be cut out.After the latter has been cut out, the device is slid axially in thedistal direction so as to position the prosthetic valve at theappropriate point in this vessel, after which this prosthetic valve isdeployed. The device is then withdrawn and the cut-out native valve isrecovered.

As a preference, said elongate support element is a tubular catheter.

This catheter thus allows the blood to flow through it during the timethat the native valve is being cut away.

The cross section of the passage through this catheter may be largeenough to allow the blood to flow through this passage, thus limiting oravoiding having to place the patient on extra corporal circulation. Thecatheter may also have a smaller diameter, making it easier for thedevice to be introduced into and slid along the bodily vessel, but itthen becomes necessary to provide peripheral circulation through anexternal assistance system such as an extra corporal circulation system.

The catheter comprises a lateral distal opening to allow the blood toreach the bodily vessel, for example the ascending aorta, this openingbeing formed in such a way that the length of catheter through which theblood flows is as short as possible.

As a preference, the device comprises a distal inflatable balloon,placed at the exterior face of said elongate element; this balloon isshaped to be able to occupy a furled position in which it has a crosssection such that it does not impede the sliding introduction of thedevice into said bodily vessel, and an unfurled position in which itoccupies all of the space between the exterior face of said elongateelement and the wall of said bodily vessel and, via a peripheral edgethat it comprises, bears against this wall.

The balloon is inflated after the series of blades have been positionedone on each side of the native valve, so as to prevent blood refluxduring the ablation of the native valve. When said elongate element is acatheter, this balloon also allows this blood to be made to flow onlythrough the catheter.

Once the prosthetic valve has been put in place, the balloon is returnedto its furled position so as to re-establish the flow of blood throughthe bodily vessel.

As a preference, the device comprises a distal filter made of flexiblematerial placed at the exterior face of said elongate element; thisfilter is shaped to be able to occupy a furled position in which it hasa cross section such that it does not impede the introduction andsliding of the device into and in said bodily vessel, and an unfurledposition in which it occupies all of the space between the exterior faceof said elongate element and the wall of this vessel and, via aperipheral edge that it comprises, bears against this wall.

This filter makes it possible to collect any fragments that may havebeen generated by the cutting-away of the valve, and to retain them sothat they can be removed from the blood circulation.

The device may comprise means for moving said series of blades in theaxial direction independently of said balloon and/or of said filter.Once deployed, this or these do not need to be shifted axially in thebodily vessel during the aforementioned axial moving of the series ofblades.

Said balloon and/or said filter may also be separate from the device,being mounted on an elongate support element specific to them.

In the event of operations on a mitral valve, this balloon and/or thisfilter are introduced into the aorta via a peripheral arterial route,and the device for its part is introduced into the heart through theperipheral venous system, as far as the right atrium then into the leftatrium through the interatrial septum as far as the mitral valve.

The prosthetic valve may advantageously comprise an armature made of ashape memory material, particularly a nickel-titanium alloy known by thename of “NITINOL”.

This same valve may comprise valve leaflets made of biological material(preserved animal or human valve leaflets) or valve leaflets made of asynthetic material such as a polymer.

For a good understanding thereof, the invention is described once againhereinbelow with reference to the appended schematic drawing which, byway of non-limiting example, illustrates a preferred embodiment of thedevice to which it relates.

FIG. 1 is a view of it in longitudinal section, according to a firstembodiment intended to treat a valve in the aorta;

FIG. 2 is a view of it in cross section on II—II of FIG. 1;

FIG. 3 is a view similar to FIG. 2, in another position of thesubassembly which it comprises;

FIG. 4 is a perspective view of a prosthetic valve which can be fittedusing it;

FIGS. 5 to 9 are views of it while it is positioned in a heart, at thevalve that is to be treated, during the various successive operations bymeans of which this valve is cut out and the prosthetic valve shown inFIG. 4 fitted;

FIG. 10 is a view of the prosthetic valve shown in FIG. 4, afterfitting, and

FIG. 11 is a view of the device according to another embodiment,intended for treating a mitral valve.

FIG. 12 is a detailed view of an elongate blade.

FIGS. 1 to 3 represent a device 1 for replacing a heart valve by apercutaneous route.

This device comprises a tubular catheter 2 formed from three tubes 5, 6,7 engaged one inside the other and on which there are placed, from theproximal end to the distal end (considered with respect to the flow ofblood, that is to say from right to left in FIG. 1), a prosthetic valve10, two series of blades 11, 12, a balloon 13 and a filter 14.

The three tubes 5, 6, 7 are mounted so that they can slide one insidethe other. The interior tube 5 delimits a passage 15, the cross sectionof which is large enough to allow blood to flow through it.

At the proximal end, the intermediate tube 6 forms a bell housing 6 adelimiting, with the interior tube 5, an annular cavity 17 in which theprosthetic valve 10 is contained in the furled condition.

FIG. 4 shows that this valve 10 comprises an armature 20 and valveleaflets 21 mounted so that they are functionally mobile on thisarmature 20.

The armature consists of a collection of wires 22, 23, 24 made of shapememory material, particularly of nickel-titanium alloy known by the nameof “NITINOL”, namely:

a proximal end wire 22 which, when the valve 10 is in the deployedstate, has a roughly circular shape;

a distal end wire 23 forming three corrugations in the axial direction,these corrugations being distributed uniformly around the circumferenceof the valve 10, and

an intermediate wire 24 forming longitudinal corrugations between thewires 22 and 23, this wire 24 being connected to the latter ones via theends of each of these corrugations.

The valve leaflets 21 for their part are made of biological material(preserved human or animal valve leaflets) or of synthetic material,such as a polymer.

The armature 20 may, when its material is cooled, be radially contractedso that the valve 10 can enter the cavity 17. When this material isheated to body temperature, this armature 20 returns to its originalshape, depicted in FIG. 4, in which it has a diameter matched to that ofa bodily vessel, particularly the aorta, in which the native valve thatis to be treated lies. This diameter of the armature 20 is such that thevalve 10 bears against the wall of the bodily vessel and is immobilizedin the axial direction with respect to that vessel.

Each series of blades 11, 12 comprises metal elongate blades 30 and aninflatable balloon 31 situated between the catheter 2 and these blades30.

The blades 30 have a curved profile and are arranged on thecircumference of the catheter 2.

The blades 30 of the proximal series 11 are connected pivotably to thetube 6 by their proximal ends and comprise a cutting distal edge 30 a,while the blades 30 of the distal series 12 are connected pivotably tothe exterior tube 7 by their distal ends and comprise a cutting proximaledge 30 b.

The connection between the blades 30 and the respective tubes 6 and 7 isachieved by welding the ends of the blades 30 together to form a ring,this ring being fixed axially to the corresponding tube 6, 7 by crimpingthis ring onto this tube 6, 7, the pivoting of the blades 30 beingachieved by simple elastic deformation of these blades 30.

This pivoting can take place between a position in which the blades 30are furled, radially internally with respect to the catheter 2 and shownin FIGS. 1 and 2, and a position in which these blades 30 are unfurled,radially externally with respect to this catheter 2 and shown in FIG. 3.In the furled position, the blades 30 lie close to the wall of the tube6 and partially overlap each other so that they do not impede theintroduction and the sliding of the device 1 into and in the bodilyvessel in which the native valve that is to be treated lies; in saidunfurled position, the blades 30 are deployed in a corolla so that theircutting edges 30 a, 30 b are placed in the continuation of one anotherand thus constitute a circular cutting edge visible in FIG. 3.

Each balloon 31, placed between the tube 3 and the blades 30, may beinflated from the end of the catheter 2 which emerges from the patient,via a passage 32 formed in the tube 6. It thus, when inflated, allowsthe blades 30 to be brought from their furled position into theirunfurled position, and performs the reverse effect when deflated.

The axial sliding of the tube 6 with respect to the tube 7 allows theseries of blades 11, 12 to be moved axially toward one another, betweena spaced-apart position shown in FIG. 1, and a close-together position.In the former of these positions, one series of blades 11 may be placedaxially on one side of the native valve while the other series of blades12 is placed axially on the other side of this valve, whereas in thelatter of these positions, the circular cutting edges of these twoseries of blades 11, 12 are brought into mutual contact and thus cutthrough the native valve in such a way as to detach it from said bodilyvessel.

The tubes 5 to 7 further comprise marks (not visible in the figures) inbarium sulfate allowing the axial position of the device 1 with respectto the native valve to be identified percutaneously so that each of thetwo series of blades 11, 12 can be placed on one axial side of thisvalve.

These tubes 5 to 7 also comprise lateral distal openings (not depicted)to allow the blood to reach the bodily vessel, these openings beingformed in such a way that the length of catheter 2 through which theblood flows is as short as possible, that is to say immediately afterthe filter 14, in the distal direction.

The balloon 13 is placed on the exterior face of the tube 7, distallywith respect to the series 12. This balloon 13 has an annular shape andis shaped to be able to occupy a furled position in which it has a crosssection such that it does not impede the introduction and sliding of thedevice 1 into and in said bodily vessel, and an unfurled position, inwhich it occupies all of the space between the exterior face of the tube7 and the wall of said bodily vessel and, via a peripheral edge 13 awhich it comprises, bears against this wall.

The filter 14 is placed distally with respect to the balloon 13, on thetube 7, to which it is axially fixed. This filter 14 is made of flexiblematerial, for example polyester netting, and is shaped to be able tooccupy a furled position in which it has a cross section such that itdoes not impede the introduction and sliding of the device 1 into and insaid bodily vessel, and an unfurled position in which it occupies all ofthe space between the exterior face of the catheter 2 and the wall ofthis vessel and, via a peripheral edge 14 a which it comprises, bearsagainst this wall.

An inflatable balloon 35 is placed between the tube 7 and the filter 14so as, depending on whether it is inflated or deflated, to bring thefilter 14 into its respective unfurled and furled positions.

In practice, as shown by FIGS. 5 to 9, the device 1 is introduced intosaid bodily vessel 50 by a percutaneous route and is slid along insidethis vessel 50 until each of the series 11, 12 of blades is placed onone side of the native valve 55 that is to be treated (FIG. 5). Thisposition is identified using the aforementioned marks.

When the device is in this position, the proximal part of the catheter 2is situated in the heart, preferably in the left ventricle, while theaforementioned distal lateral openings are placed in a peripheralarterial vessel, preferably in the ascending aorta.

The balloons 13 and 35 are inflated in such a way as to cause blood toflow only through the passage 15 and prevent blood reflux during theablation of the valve 55. A peripheral perfusion system is set in placeto facilitate this flow.

The blades 30 of the two series 11, 12 are then deployed (FIG. 6) byinflating the balloons 31, then these two series 11, 12 are moved closertogether by sliding the tube 6 with respect to the tube 7, until thevalve 55 is cut through (FIG. 7).

The blades 30 are then returned to their furled position by deflatingthe balloons 31 while at the same time remaining in their close-togetherposition, which allows the cut-out valve 55 to be held between them.

The device 1 is then slid axially in the distal direction so as to bringthe bell housing 6 a to the appropriate position in the vessel 50 (FIG.8), after which the valve 10 is deployed by sliding the tube 6 withrespect to the tube 5 (FIG. 9).

The balloons 13 and 35 are deflated then the device 1 is withdrawn andthe cut-out valve 55 is recovered (FIG. 10).

FIG. 11 shows a second embodiment of the device 1, allowing operation ona mitral valve 56.

The same reference numerals are used to denote the same elements orparts as the aforementioned, as long as these elements or parts areidentical or similar in both embodiments.

In this case, the tubular catheter is replaced by a support wire 2, onwhich one of the series of blades is mounted and by a tube engaged overand able to slide along this wire, on which tube the other series ofblades is mounted; the passages for inflating the balloons 31 run alongthis support wire and this tube; the balloon 13 and the filter 14 areseparate from the device 1 and are introduced into the aorta via aperipheral arterial route, by means of a support wire 40 along which thepassages for inflating the balloons 13 and 35 run. The device 1, devoidof balloon 13 and the filter 14, is for its part introduced into theheart through the peripheral venous system, as far as the right atriumthen into the left atrium through the inter-auricular septum, as far asthe valve 56.

For the remainder, the device 1 operates in the same way as wasmentioned earlier.

The invention thus provides a device for replacing a heart valve by apercutaneous route, making it possible to overcome the drawbacks of theprior techniques. Indeed the device 1 is entirely satisfactory asregards the cutting-away of the valve 55, 56, making it possible tooperate without stopping the heart and making it possible, by virtue ofthe filter 14, to prevent any dispersion of valve fragments 55, 56 intothe circulatory system.

It goes without saying that the invention is not restricted to theembodiment described hereinabove by way of example but that, on thecontrary, it encompasses all alternative forms of embodiment thereof.Thus, the device may comprise a fourth tube, engaged on and able toslide along the tube 7, this fourth tube comprising the balloon and thefilter mounted on it and allowing said series of blades to be moved inthe axial direction independently of said balloon and/or of said filter;the blades may be straight as depicted in the drawing or may be curvedtoward the axis of the device at their end which has the cutting edge,so as to eliminate any risk of lesion in the wall of the bodily vessel,as shown in FIG. 12; the filter 14 may be of the self-expanding type andnormally kept in the contracted position by a sliding tube, which coversit, making the balloon 35 unnecessary.

What is claimed is:
 1. A device (1) for replacing, via a percutaneousroute, a heart valve (55, 56) located in a bodily vessel (50),characterized in that it comprises: an elongate support element (2); afirst series (11) of elongate blades (30) arranged around thecircumference of said elongate element (2); these blades (30) arepivotably connected to said elongate element (2) at their proximallongitudinal end and each have a cutting edge (30 a) at their distallongitudinal end; said blades (30) capable of pivoting with respect tosaid elongate element (2) between a furled position in which they arenear to the wall of the elongate element (2) so that they do not impedethe introduction and sliding of the device (1) into and in the bodilyvessel (50) in which a valve (55, 56) is located, particularly withinthe aorta, and an unfurled position in which these blades (30) aredeployed into a corolla in such a way that their cutting edges (30 a)are placed in the continuation of one another and thus constitute acircular cutting edge; a second series (12) of blades (30) which isarranged after said first series (11) of blades in the distal direction;the blades (30) of this second series (12) of blades have a structureidentical to that of the blades (30) of said first series (11) of bladesexcept that these blades (30) of this second series (12) are connectedto said elongate element by their distal longitudinal end and each havea cutting edge (30 b) at their proximal longitudinal end; means (31) forbringing the blades (30) of said first and second series (11, 12) ofblades from a furled position to an unfurled position; means (6, 7) formoving said series (11, 12) of blades axially toward one another,between a position in which these series (11, 12) of blades are awayfrom each other and in which one series (11) of blades can be placedaxially on one side of the native valve (55, 56) while the other series(12) of blades is placed axially on the other side of this valve (55,56), and a close-together position in which the circular cutting edgesof these two series (11, 12) of blades are brought into mutual contactand thus cut through the native valve (55, 56) so as to detach it fromsaid bodily vessel (50); and means of identifying, by a percutaneousroute, the axial position of the device (1) with respect to the nativevalve (55, 56) so as to position each of the two aforementioned series(11, 12) of blades on one side of this valve.
 2. The device (1) asclaimed in claim 1, characterized in that it comprises a proximalprosthetic valve (10), with a radially deployable structure, it beingpossible for this prosthetic valve (10) to occupy a furled position inwhich it is near the wall of said elongate element (2) and does notimpede the introduction and sliding of the device (1) into and in saidbodily vessel (50), and an unfurled position in which it bears againstthe wall of this vessel (50) and is able to replace the native heartvalve (55, 56).
 3. The device as claimed in claim 1, characterized inthat said elongate support element is a tubular catheter (2).
 4. Thedevice as claimed in claim 1, characterized in that it comprises adistal inflatable balloon (13), placed at the exterior face of saidelongate element (2); this balloon (13) is shaped to be able to occupy afurled position in which it has a cross section such that it does notimpede the sliding introduction of the device (1) into said bodilyvessel (50), and an unfurled position in which it occupies all of thespace between the exterior face of said elongate element (2) and thewall of said bodily vessel (50) and, via a peripheral edge (13 a) thatit comprises, bears against this wall.
 5. The device as claimed in claim1, characterized in that it comprises a distal filter (14) made offlexible material placed at the exterior face of said elongate element(2); this filter (14) is shaped to be able to occupy a furled positionin which it has a cross section such that it does not impede theintroduction and sliding of the device (1) into and in said bodilyvessel (50), and an unfurled position in which it occupies all of thespace between the exterior face of said elongate element (2) and thewall of this vessel (50) and, via a peripheral edge (14 a) that itcomprises, bears against this wall.
 6. The device as claimed in claim 4,characterized in that it comprises means for moving said series ofblades in the axial direction independently of said balloon and/or ofsaid filter.
 7. The device as claimed in claim 4, characterized in thatsaid balloon (13) and/or said filter (14) are mounted on an elongatesupport element specific to them and are separate from the device (1).8. The device as claimed in claim 2, characterized in that theprosthetic valve (10) comprises an armature (20) made of a shape memorymaterial, particularly a nickel-titanium alloy known by the name of“NITINOL”.
 9. The device as claimed in claim 2, characterized in thatthe prosthetic valve (10) comprises valve leaflets (21) made ofbiological material (preserved animal or human valve leaflets) or valveleaflets made of a synthetic material such as a polymer.
 10. The deviceas claimed in claim 1, characterized in that the blades are curvedtoward the axis of the device at their end that has the cutting edge.11. The device as claimed in claim 3, characterized in that the cathetercomprises a lateral distal opening to allow the blood to reach thebodily vessel, for example the ascending aorta, this opening beingformed in such a way that the length of catheter through which the bloodflows is as short as possible, and so as to allow the blood to flowbetween the heart and a peripheral vessel.